DIAGNOSTIC EVALUATION OF EXTRAPULMONARY TUBERCULOSIS: A COMPARATIVE STUDY OF FNAC, ZN STAINING, AND CB-NAAT TECHNIQUES
DOI:
https://doi.org/10.22159/ijcpr.2026v18i1.8055Keywords:
EPTB, FNAC, ZN staining, CBNAAT, Tuberculosis diagnosisAbstract
Objective: To evaluate and compare the diagnostic efficacy of Fine Needle Aspiration Cytology (FNAC), Ziehl–Neelsen (ZN) staining, and Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) in the diagnosis of extrapulmonary tuberculosis (EPTB).
Methods: A prospective observational study was conducted on clinically suspected EPTB cases. FNAC smears were examined cytologically, ZN staining was performed for acid-fast bacilli, and CBNAAT was used for molecular detection of Mycobacterium tuberculosis and rifampicin resistance.
Results: FNAC showed high sensitivity and rapid diagnostic utility, especially in resource-limited settings. ZN staining demonstrated very high sensitivity and strong rule-out value, but lower specificity. CBNAAT exhibited the highest specificity and reliably identified rifampicin resistance, making it the most effective confirmatory test. Higher EPTB incidence was observed among females.
Conclusion: A tiered approach-initial screening with FNAC or ZN staining followed by CBNAAT confirmation—provides accurate, feasible, and cost-effective EPTB diagnosis.
Downloads
References
1. Denkinger CM, Schumacher SG, Boehme CC, Dendukuri N, Pai M, Steingart KR. Xpert MTB/RIF assay for the diagnosis of extrapulmonary tuberculosis: a systematic review and meta-analysis. Eur Respir J. 2014 Aug;44(2):435-46. doi: 10.1183/09031936.00007814.
2. Rajendra Prasad Takhar. NAAT: a new ray of hope in the early diagnosis of EPTB. Emergency Medicine: Open Access. 2016;6(4):1000328. doi: 10.4172/2165-7548.1000328.
3. Salinita N, Supriya L, Usharani M, Singh HL. Detection of pulmonary tuberculosis using cartridge-based nucleic acid amplification test (CBNAAT) and fluorescent microscopy. Int J Health Res Medico Legal Pract. 2018;4(1):78-81.
4. Xpert MTB/RIF implementation manual technical and ‘how-to’; practical considerations. In: Geneva World Health Organization; 2014.
5. Sharma SK, Mohan A, Kohli M. Extrapulmonary tuberculosis. Expert Rev Respir Med. 2021;15(7):931-48. doi: 10.1080/17476348.2021.1927718, PMID 33966561.
6. Cohen A, Mathiasen VD, Schon T, Wejse C. The global prevalence of latent tuberculosis: a systematic review and meta-analysis. Eur Respir J. 2019;54(3):1900655. doi: 10.1183/13993003.00655-2019.
7. Tadesse M. Improving the diagnosis of tuberculosis in hard to diagnose populations: clinical evaluation of GeneXpert MTB/RIF and alternative approaches in Ethiopia. University of Antwerp; 2018.
8. Rao CM, Thakur B, Subhankar S, Dash DP. Pattern of extra-pulmonary tuberculosis among urban population with special reference to CBNAAT as a diagnostic tool: a retrospective study at a Tertiary Care Hospital of Odisha, India. Int J Res Med Sci. 2018 Oct;6(10):3375-80. doi: 10.18203/2320-6012.ijrms20184049.
9. Sahukar SB, Palani VK, Ranganathan R, Kumpthala S. Clinical profile of extra pulmonary tuberculosis: a retrospective south Indian study. Sahukar. 2022;7(2):117-21.
10. Solovic I, Jonsson J, Korzeniewska Kosela M, Chiotan DI, Pace Asciak A, Slump E. Challenges in diagnosing extrapulmonary tuberculosis in the European Union, 2011. Eurosurveillance. 2013 Mar 21;18(12):20432. doi: 10.2807/ese.18.12.20432-en.
Published
How to Cite
Issue
Section
This work is licensed under a Creative Commons Attribution 4.0 International License.